/*
** $Id: loslib.c,v 1.65.1.1 2017/04/19 17:29:57 roberto Exp $
** Standard Operating System library
** See Copyright Notice in lua.h
*/

#define loslib_c
#define LUA_LIB

#include "lprefix.h"

#include <errno.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

/*
** {==================================================================
** List of valid conversion specifiers for the 'strftime' function;
** options are grouped by length; group of length 2 start with '||'.
** ===================================================================
*/
#if !defined(LUA_STRFTIMEOPTIONS) /* { */

/* options for ANSI C 89 (only 1-char options) */
#define L_STRFTIMEC89 "aAbBcdHIjmMpSUwWxXyYZ%"

/* options for ISO C 99 and POSIX */
#define L_STRFTIMEC99 "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%" \
                      "||"                                    \
                      "EcECExEXEyEY"                          \
                      "OdOeOHOIOmOMOSOuOUOVOwOWOy" /* two-char options */

/* options for Windows */
#define L_STRFTIMEWIN "aAbBcdHIjmMpSUwWxXyYzZ%" \
                      "||"                      \
                      "#c#x#d#H#I#j#m#M#S#U#w#W#y#Y" /* two-char options */

#if defined(LUA_USE_WINDOWS)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEWIN
#elif defined(LUA_USE_C89)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC89
#else /* C99 specification */
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC99
#endif

#endif /* } */
/* }================================================================== */

/*
** {==================================================================
** Configuration for time-related stuff
** ===================================================================
*/

#if !defined(l_time_t) /* { */
/*
** type to represent time_t in Lua
*/
#define l_timet lua_Integer
#define l_pushtime(L, t) lua_pushinteger(L, (lua_Integer)(t))

static time_t l_checktime(lua_State *L, int arg)
{
  lua_Integer t = luaL_checkinteger(L, arg);
  luaL_argcheck(L, (time_t)t == t, arg, "time out-of-bounds");
  return (time_t)t;
}

#endif /* } */

#if !defined(l_gmtime) /* { */
/*
** By default, Lua uses gmtime/localtime, except when POSIX is available,
** where it uses gmtime_r/localtime_r
*/

#if defined(LUA_USE_POSIX) /* { */

#define l_gmtime(t, r) gmtime_r(t, r)
#define l_localtime(t, r) localtime_r(t, r)

#else /* }{ */

/* ISO C definitions */
#define l_gmtime(t, r) ((void)(r)->tm_sec, gmtime(t))
#define l_localtime(t, r) ((void)(r)->tm_sec, localtime(t))

#endif /* } */

#endif /* } */

/* }================================================================== */

/*
** {==================================================================
** Configuration for 'tmpnam':
** By default, Lua uses tmpnam except when POSIX is available, where
** it uses mkstemp.
** ===================================================================
*/
#if !defined(lua_tmpnam) /* { */

#if defined(LUA_USE_POSIX) /* { */

#include <unistd.h>

#define LUA_TMPNAMBUFSIZE 32

#if !defined(LUA_TMPNAMTEMPLATE)
#define LUA_TMPNAMTEMPLATE "/tmp/lua_XXXXXX"
#endif

#define lua_tmpnam(b, e)           \
  {                                \
    strcpy(b, LUA_TMPNAMTEMPLATE); \
    e = mkstemp(b);                \
    if (e != -1)                   \
      close(e);                    \
    e = (e == -1);                 \
  }

#else /* }{ */

/* ISO C definitions */
#define LUA_TMPNAMBUFSIZE L_tmpnam
#define lua_tmpnam(b, e)     \
  {                          \
    e = (tmpnam(b) == NULL); \
  }

#endif /* } */

#endif /* } */
/* }================================================================== */

static int os_execute(lua_State *L)
{
  const char *cmd = luaL_optstring(L, 1, NULL);
  int stat = system(cmd);
  if (cmd != NULL)
    return luaL_execresult(L, stat);
  else
  {
    lua_pushboolean(L, stat); /* true if there is a shell */
    return 1;
  }
}

static int os_remove(lua_State *L)
{
  const char *filename = luaL_checkstring(L, 1);
  return luaL_fileresult(L, remove(filename) == 0, filename);
}

static int os_rename(lua_State *L)
{
  const char *fromname = luaL_checkstring(L, 1);
  const char *toname = luaL_checkstring(L, 2);
  return luaL_fileresult(L, rename(fromname, toname) == 0, NULL);
}

static int os_tmpname(lua_State *L)
{
  char buff[LUA_TMPNAMBUFSIZE];
  int err;
  lua_tmpnam(buff, err);
  if (err)
    return luaL_error(L, "unable to generate a unique filename");
  lua_pushstring(L, buff);
  return 1;
}

static int os_getenv(lua_State *L)
{
  lua_pushstring(L, getenv(luaL_checkstring(L, 1))); /* if NULL push nil */
  return 1;
}

static int os_clock(lua_State *L)
{
  lua_pushnumber(L, ((lua_Number)clock()) / (lua_Number)CLOCKS_PER_SEC);
  return 1;
}

/*
** {======================================================
** Time/Date operations
** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,
**   wday=%w+1, yday=%j, isdst=? }
** =======================================================
*/

static void setfield(lua_State *L, const char *key, int value)
{
  lua_pushinteger(L, value);
  lua_setfield(L, -2, key);
}

static void setboolfield(lua_State *L, const char *key, int value)
{
  if (value < 0) /* undefined? */
    return;      /* does not set field */
  lua_pushboolean(L, value);
  lua_setfield(L, -2, key);
}

/*
** Set all fields from structure 'tm' in the table on top of the stack
*/
static void setallfields(lua_State *L, struct tm *stm)
{
  setfield(L, "sec", stm->tm_sec);
  setfield(L, "min", stm->tm_min);
  setfield(L, "hour", stm->tm_hour);
  setfield(L, "day", stm->tm_mday);
  setfield(L, "month", stm->tm_mon + 1);
  setfield(L, "year", stm->tm_year + 1900);
  setfield(L, "wday", stm->tm_wday + 1);
  setfield(L, "yday", stm->tm_yday + 1);
  setboolfield(L, "isdst", stm->tm_isdst);
}

static int getboolfield(lua_State *L, const char *key)
{
  int res;
  res = (lua_getfield(L, -1, key) == LUA_TNIL) ? -1 : lua_toboolean(L, -1);
  lua_pop(L, 1);
  return res;
}

/* maximum value for date fields (to avoid arithmetic overflows with 'int') */
#if !defined(L_MAXDATEFIELD)
#define L_MAXDATEFIELD (INT_MAX / 2)
#endif

static int getfield(lua_State *L, const char *key, int d, int delta)
{
  int isnum;
  int t = lua_getfield(L, -1, key); /* get field and its type */
  lua_Integer res = lua_tointegerx(L, -1, &isnum);
  if (!isnum)
  {                    /* field is not an integer? */
    if (t != LUA_TNIL) /* some other value? */
      return luaL_error(L, "field '%s' is not an integer", key);
    else if (d < 0) /* absent field; no default? */
      return luaL_error(L, "field '%s' missing in date table", key);
    res = d;
  }
  else
  {
    if (!(-L_MAXDATEFIELD <= res && res <= L_MAXDATEFIELD))
      return luaL_error(L, "field '%s' is out-of-bound", key);
    res -= delta;
  }
  lua_pop(L, 1);
  return (int)res;
}

static const char *checkoption(lua_State *L, const char *conv,
                               ptrdiff_t convlen, char *buff)
{
  const char *option = LUA_STRFTIMEOPTIONS;
  int oplen = 1; /* length of options being checked */
  for (; *option != '\0' && oplen <= convlen; option += oplen)
  {
    if (*option == '|') /* next block? */
      oplen++;          /* will check options with next length (+1) */
    else if (memcmp(conv, option, oplen) == 0)
    {                            /* match? */
      memcpy(buff, conv, oplen); /* copy valid option to buffer */
      buff[oplen] = '\0';
      return conv + oplen; /* return next item */
    }
  }
  luaL_argerror(L, 1,
                lua_pushfstring(L, "invalid conversion specifier '%%%s'", conv));
  return conv; /* to avoid warnings */
}

/* maximum size for an individual 'strftime' item */
#define SIZETIMEFMT 250

static int os_date(lua_State *L)
{
  size_t slen;
  const char *s = luaL_optlstring(L, 1, "%c", &slen);
  time_t t = luaL_opt(L, l_checktime, 2, time(NULL));
  const char *se = s + slen; /* 's' end */
  struct tm tmr, *stm;
  if (*s == '!')
  { /* UTC? */
    stm = l_gmtime(&t, &tmr);
    s++; /* skip '!' */
  }
  else
    stm = l_localtime(&t, &tmr);
  if (stm == NULL) /* invalid date? */
    return luaL_error(L,
                      "time result cannot be represented in this installation");
  if (strcmp(s, "*t") == 0)
  {
    lua_createtable(L, 0, 9); /* 9 = number of fields */
    setallfields(L, stm);
  }
  else
  {
    char cc[4]; /* buffer for individual conversion specifiers */
    luaL_Buffer b;
    cc[0] = '%';
    luaL_buffinit(L, &b);
    while (s < se)
    {
      if (*s != '%') /* not a conversion specifier? */
        luaL_addchar(&b, *s++);
      else
      {
        size_t reslen;
        char *buff = luaL_prepbuffsize(&b, SIZETIMEFMT);
        s++;                                   /* skip '%' */
        s = checkoption(L, s, se - s, cc + 1); /* copy specifier to 'cc' */
        reslen = strftime(buff, SIZETIMEFMT, cc, stm);
        luaL_addsize(&b, reslen);
      }
    }
    luaL_pushresult(&b);
  }
  return 1;
}

static int os_time(lua_State *L)
{
  time_t t;
  if (lua_isnoneornil(L, 1)) /* called without args? */
    t = time(NULL);          /* get current time */
  else
  {
    struct tm ts;
    luaL_checktype(L, 1, LUA_TTABLE);
    lua_settop(L, 1); /* make sure table is at the top */
    ts.tm_sec = getfield(L, "sec", 0, 0);
    ts.tm_min = getfield(L, "min", 0, 0);
    ts.tm_hour = getfield(L, "hour", 12, 0);
    ts.tm_mday = getfield(L, "day", -1, 0);
    ts.tm_mon = getfield(L, "month", -1, 1);
    ts.tm_year = getfield(L, "year", -1, 1900);
    ts.tm_isdst = getboolfield(L, "isdst");
    t = mktime(&ts);
    setallfields(L, &ts); /* update fields with normalized values */
  }
  if (t != (time_t)(l_timet)t || t == (time_t)(-1))
    return luaL_error(L,
                      "time result cannot be represented in this installation");
  l_pushtime(L, t);
  return 1;
}

static int os_difftime(lua_State *L)
{
  time_t t1 = l_checktime(L, 1);
  time_t t2 = l_checktime(L, 2);
  lua_pushnumber(L, (lua_Number)difftime(t1, t2));
  return 1;
}

/* }====================================================== */

static int os_setlocale(lua_State *L)
{
  static const int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY,
                            LC_NUMERIC, LC_TIME};
  static const char *const catnames[] = {"all", "collate", "ctype", "monetary",
                                         "numeric", "time", NULL};
  const char *l = luaL_optstring(L, 1, NULL);
  int op = luaL_checkoption(L, 2, "all", catnames);
  lua_pushstring(L, setlocale(cat[op], l));
  return 1;
}

static int os_exit(lua_State *L)
{
  int status;
  if (lua_isboolean(L, 1))
    status = (lua_toboolean(L, 1) ? EXIT_SUCCESS : EXIT_FAILURE);
  else
    status = (int)luaL_optinteger(L, 1, EXIT_SUCCESS);
  if (lua_toboolean(L, 2))
    lua_close(L);
  if (L)
    exit(status); /* 'if' to avoid warnings for unreachable 'return' */
  return 0;
}

static const luaL_Reg syslib[] = {
    {"clock", os_clock},
    {"date", os_date},
    {"difftime", os_difftime},
    {"execute", os_execute},
    {"exit", os_exit},
    {"getenv", os_getenv},
    {"remove", os_remove},
    {"rename", os_rename},
    {"setlocale", os_setlocale},
    {"time", os_time},
    {"tmpname", os_tmpname},
    {NULL, NULL}};

/* }====================================================== */

LUAMOD_API int luaopen_os(lua_State *L)
{
  luaL_newlib(L, syslib);
  return 1;
}
